A typical mass flow controller (MFC) is a closed-loop device that sets, measures, and controls the flow of a gas in industrial processes such as thermal and dry etching. An important part of a MFC is a sensor that measures the mass flow rate of the gas flowing through the device. The MFC compares an output signal from the sensor with a predetermined set point and adjusts a control valve to maintain the mass flow rate of the gas at the predetermined set point.